Mountain Grove is a city in southwestern Texas and southeastern Wright counties in the U.S. state of Missouri, located in the south central section of the state. The population was 4,789 at the 2010 census.
A post office called Mountain Grove has been in operation since 1875. The community owes its present name to a stand of trees near the original elevated town site.
In 1841 a settlement was built on land east of Mountain Grove near a spring in a grove of hickory timber. A post office was established in Hickory Spring in 1853. The post office, in 1878, was named for Judge Robert W. Fyan, a prominent figure in early county history. In 1859, a general store was built at the crossroads about one mile west of Hickory Spring. The old post office established under the name of Fyan before the Civil War changed to Mountain Grove, with reference to its location on a ridge in a grove of trees, in 1878.
This became known as the "mountain store, mountain grove or the mountain" due to its elevation of 1,525 feet (465 m). One of the most famous incidents in Mountain Grove occurred in the middle of May 1883, when what was called a "nipping frost" caused every tree, sapling and shrub in the community of Fyan and the Fyan depot to be cut clean as from an axe. Thus, the joining of Mountain Grove and adjoining Fyan occurred.